Yes you can
I know you need a 2gb to hack the Wii but after hacking could I go bigger? Say maybe 4 or 8gb?
I used a 16GB Class 6 SDHC to hack my Wii (Letterbomb) and I still use it with homebrew apps. Surprisingly, I haven't run into any problems with it.
I recommend using a good name brand (e.g: SanDisk) and the official SD card formatter
Wii: Mario Kart Wii Bundle (Black, 4.3U), SM: 4.1U, HBC: v1.0.8,
cIOS: d2x v8 beta (r41), Priiloader: Priiloader v0.7, SDHC: SanDisk Ultra 16GB Class 6,
USB HDD: Seagate Expansion 500GB (ST905004EXA101-RK), Loader: USB Loader GX r1147